Azo pigment dyestuff and coating composition



Patented June 6, 1944 UNiTED STAT ES PATENT OFFICE AZO PIGMENT DYESTUFF AND COATING COMPOSITION.

Grady M. ONeal, Chicago, Ill., a'ssignor to The Sherwin-Williams Company, Cleveland, Ohio,

a. corporation Ohio No Drawing. Application March 17, 1943, Serial No. 479,497

22 Claims. (01. 106-219) This invention relates to azo pigment dyestuffs of both the salt and non-salt forms and of both lake and non-lake forms, and so coat- 'ment dyestufi, or both. This may be accomplished in a variety of ways depending upon the particular procedure which it is desired to employ in making the materials.

In my cofiled application, Serial No. 479,493, I have disclosed and claimed a'generic' invention based upo'n the discovery that water-insoluble, rosinic-fatty type acid, metallic soaps possess new and valuable properties in combination with azo pigment dyestufi. In my cofiled applications, Serial Nos. 479,495, and 479,496, I have disclosed and claimed two met processes by means of which the said generic invention can be advantageously employed to produce azo pigment dyestuffs of the non-lake type and the lake type. While the two wet processes of the last mentioned applications are of great value and demonstrate outstanding ad vantages in certain pigment manufacturing operations, they possess a number of characteristics which tend to limit their fields of usefulness. For example, neither of these procedures is readily'applicable to treating the alkali-metal salt-forms of'azo pigment dyestufls.

In my coflled application, Serial No.j479,49 8, I have disclosed and claimed a dry process, and

the product thereof, for combining rosinic fatty type acid, metallic, soap powders with pigment powders. In .my coflled applications, Serial Nos.

479,494 and: 479,499, 'I' have disclosed and claimed certain specific types of rosinic-fatty type acid metallic soap powders useful in carrying out the invention of my application, Serial No. 479,498, mentioned above.

In each of the several applications referred to, mention is made of a discovery involving the use of salt electrolyte to bring about certain improvements in azo pigment dyestuffs and coat-,

of these applications certain of the claims have been directed to the adaptation of this discovery to the respective inventions of those applications.

The present application is intended to cover the use of salt electrolyte broadly in the processes and withproducts of my various other applications, as well as in still other processes and with other products not described in said.

applications.-

As indicated inthe foregoing discussion, the

principal object of this invention is to improve azo pigment dyestuffs by a, change in the prior art processe whichchange, requires no additional operation and which, according to one embodiment of my invention, involves the elimination of a conventional prior art operation.

A more specific object of the invention isto produce azo pigment dyestuffs having improved wetting properties toward vehicles for coating compositions, bettered dispersion, and lessened emulsification tendencies -when incorporated into a vehicle.

It is generally the object of the. present invention to associate azo pigment dyestufl, salt electrolyte, and water-insoluble metallic soap at any stage prior to completely dispersing the azo pigment dyestufis into a non-aqueous liquid vehicle for a coating composition.

Various other objects and advantages will be sary. The pigment dyestuif resulting from the final processing by this well hiown procedure is then filtered, giving a pigment dyestufi press cake or pulp. A procedure is normally employed at the end of the filtering operation to wash the pigment press-cake free from soluble salts, alkali,

or acid. In the case of certain azo pigment dyestufl's, the accomplishment of this aim is rather lengthy and drawn out. The idea behind the washing step, and the one generally held throughout the industry, is that an acid or alkaline press cake containing soluble salts, when further processed, results in coating compositions which are diiilcult to grind or disperse into a veing compositions made therefrom, and in each hicle and show a marked tendency to set-up,

skin, and generally give poor working proporties. However, I have found, surprisingly enough, that under certain conditions this previous concept or notion is not entirelytrue; rather, the opposite is true when a water-insoluble metal soap is present. I do not mean to say that the conditions of acidity and alkalinity in a pigment press cake or pulp do not have a considerable effect upon the properties of a coating composi-- tion; but I have found that salt electrolyte can assumes and non-lake forms are those having less or no be present to great advantage in giving improved pigment coating compositions when water-insoluble metallicsoap is present. The presence of salt electrolyte produces some slight improvement in the wetting and dispersion properties of an azo pigment dyestufi having no such soap associated therewith. However when a water-insoluble metal soap and salt electrolyte are present with an azo pigment dyestufi in the dispersion into a liquid vehicle and in the resulting composition, a marked improvement has been' observed due to the intentional presence of salt electrolyte. And, further, with an azo pigment dyestuif which has salt electrolyte and a waterinsoluble metallic soap of a rosinic-fatty type acid nature associated therewith, improvements 1 of a very marked degree are obtained. In fact,

the use of salt electrolyte and rosinic-fatty type acid soap permits the manufacture of an entirely new series of azo pigment dyestufis which have hitherto been desired but unattained. Not

only do these new azo pigment dyestuifs possess all the tinctorial properties of the old type of pigments, but, in addition, the coating compositions made therefrom possess one or more of these improvements: improved or.easier dispersion of the pigment into a vehicle; bettered working properties, such as softer body, outstanding flow, and decreased set-up; enhanced film gloss; and, in certain instances, greater lithographic breakdown resistance.

extender. This definition is made because the art is not definite on the point.

The advantages of using a water-insoluble metallic soap may be accomplished by producing an azo pigment dyestuff which embodies within as a separate ingredient in compounding an ink or a coating composition where salt electrolyte is also present. Salt electrolyte also may be used In printing, good ink flow of great value becauseinks which flow readily from the fountain to the inking rollers enable impressions to be made more smoothly and rapidly. Also, in other types of coating compositions, the user is enabled to incorporate higher percentages of pigment into a given vehicle and still maintain the flow properties of the old type of coating composition. In addition, the feature of incorporating higher percentages of pigment into a given vehicle enables a manufacturer of coating compositions, such as one making use oftoner base inks, to have more freedom in formulating a specific ink composition. In the manufacture of Y lessened set-up and excellence of body flow, aside chemical derivatives of rosin or abietic acid.

from the economic factor, facilitate the removal V of a toner base ink from its original container. Iesslossbyskinningandadhesiontothecontainer occurs, less labor is employed, and other economic factors are favorable.

The term azo pigment rhestufli" includes both the salt and non-salt forms. Such pigments may be extended, as by subsu'ati or diluents, with organic or inorganic materials. obtain various efiects. Organic materinlscommonly employed are various soaps, such as the rosinates, para, and fatty acid types. Inorgnnicmaterlals are, for example, blanc flxe, hydrate, aluminum phosphate, carbonate. and

others. Substrata are present in sizable amounts, upwardsby weight of 10 parts toashighaslflflparlsofsoap-formingacidto parts of pigment, and occasionally in even it? .acidsin as a seperate ingredient in compounding the pigment, the soap, and vehicle. Thus, the azo pigment dyestuif, as one ingredient, may be mixed with the soap, as another ingredient, and salt electrolyte, as a third ingredient, to form a pigment composition. This composition, then may be used as a pigment in a formulation for an ink'or a coating composition, without departure from conventional commercial practice.

The scope of the term soap" is not clearly defined in the technical literature, and the term is loosely and often improperly employed. Since the present invention makes use of soaps, and s particularly beneficial when two special classes of soaps are employed together, I have chosen to define these special classes of soaps by defining the acids from which they are derived, and have identified the two classes respectively by the terms rosinic acid" and fatty type acid."

By the term rosinic acid," as used in this application, I intend to include rosin and abietic acid; modifications of rosin, such as heat-modified rosin and solvent-extracted rosin; chemical derivatives of rosin, such as hydrogenated rosin or abietic acid; the complex soap-forming acids resulting from the condensation product of main or abietic acid with unsaturated aliphatic acids having up to, but not more than, two carboxyl groups, as described hereinafter; and other A special class of these chemical derivatives of rosin and abieticacid is covered in my cofiled application, Serial No. 479,499, wherein unsaturated ofits anhydride,is condensedwlthroslntoglve the complex soap-forming acid directly. In a second example, a typical mixture or. unsatu. t 118 1 aliphatic. lic' acidstbatarecommonmdryingoilsiscondensed (theglycerideestersoftbeseacidsbeingemployedinthis) withrosintoslveacmdensation-polymerglycerldeestenthismterbeingthensawithalkalitogivethedeaimd complexsoap-fornnngacids. Itispocslblefom other esterformsod these aliphatic efiectingthdrwlthrmln orabieticaclianditlsmt thnttbese mtersbethoseofunsaturamlmgchalmnllphatiallcacids. Fin-,1:

possible to form the identical maleic acid-abietlc acid condensation product obtained by reacting maleic anhydride with abietic acid by condensing, instead, the dimethyl ester of maleic acid with abietic acid to give the ester adduct, and then subsequently saponifying the ester adduct with alkali. All of this is well known. In the case of linseed oil, which was employed in the second example just referred to and which is illustrative of the drying oils, two unsaturated aliphatic acids are mainly present-linolic or 9:12-octadecadienoic acid, and llnolenic or 9:12:15-octadecatrienoic acid. Linolic acid is an unsaturated, monocarboxylic acid of the general type, CnHh-SCQOH; and linolenic acid is an unsaturated monocarboxylic acid of the general t pe. Gama-5000K. Hence it is seen that a large number of complex soap-forming acids capable of forming waterpinsoluble metallic soaps for the purposes of this invention, are available.

All of these various types of simple and complex acids are contemplated by the use of the term rosinic acid in thisspecificatlon and in the claims which follow.

The term "fatty type acid, for the purposes of the present invention, contemplates: (l) thevarious a,,8-llnS8tlllated aliphatic acids having up to, but not more than, two carboxyl groups, such as maleic acid, crotonic 1 acid, acetylene dicarboxylic acid, citraconic acid, and th like, which are capable of being condensed with rosin or abietic acid by the Dials-Alder reaction (described hereinafter, and also in more detail in my cofiled application Serial No. 479,499); (2) the saturated and unsaturated soap-forming aliphatic acids, which have at least 8 carbon atoms including a carboxyl group carbon in an open carbon chain,

such as caprylic acid, ricinoleic acid, oleic acid,

linolic acid, linolenic acid, palmitic acid, and the like; and (31 the soap-forming naphthenic acids, defined hereinafter, and others of a cycloaliphatic nature, each carboxyl group of which is attached to the cyclic carbon chain through at least one intermediate-carbon atomso that each carboxyl g oup i part of an aliphatic side chain of at least two carbon atoms. By this last mentioned limitation, I intend to include in this third class .of fatty type acids those cycloaliphatic.

compounds, such as naphthenic acids, in which the carboxyl-group is part of an aliphatic radical having at least two carbon atoms (including the carboxyl group carbon) and is not attached directly to a carbon atom of a cyclic carbon chain,

The term fatty type acid" includes in group (1) of the above definition certain short chain acids, such as maleic acid, which are not "soapforming" acids, as the latter term is generally understood. I wish to make it clear, therefore, that such acids, since they are not alone truly soap-forming," when reacted to form a metal salt, are not contemplated by the expression soap of a fatty type acid. However, they are "soap-forming acids when chemically combined with rosin, and, therefore, they are intended to be included as members of the group of "fatty type acids" useful for the purposes of the present invention. When 'chemically combined with rosin and suitably reacted with a metal, they enter into the formation of a soap Which is both rosinic and fatty type in nature and which is embraced by the broad terms rosinic-fatty type acid soap" and "soap of both a rosinic acid and a fatty type acid," as these terms are employedin this and my related applications referred to above.

Naphthenic acids are secured from petroleum during refining and are defined by Richters Organic Chemistry, vol. II (1939), p. 64, essentially as follows: They consist of saturated monocyclic acids of the general formula Cullen-:02, which have been found to be alkylated carboxylic acids of the cyclopentane series up to Curls-20:; of two paraflin-carboxylic acids CaHnO: ,and 81111402; and some bicyclic compounds of the general formula CnHaHOs ranging Ciel-1:202 to Casi-14002,

The term salt electrolyte" comprehends, gen-' erally those salts which are water-soluble and substantially neutral when ionized in aqueous solution, in particular the water-soluble salts of the alkali and the alkali-earth metals, While salts of the strong mineral acids, such as hydrochloric and nitric, are most usually illustrated in the following examples, others have been employed, such as salts of sulfuric acid or salts of weak organic acids (formic, acetic, citric, oxalic, and others). and alkali-earth metals have been used as salts of a variety of acids, such cationsbeing iron, lead, zinc, manganese, copper, and others. In general, the choice of the best specific salt electrolyte is 4 best determined experimentally.

It is well known that many or the fatty type I acids in group (2) in the preceding paragraph; both saturated and unsaturated, are found as Percentage Z-naphthol.

Nature of acid:

Oleic 4.0-10.5 Linoli 33.0-44.0 Linolenic 44.0-49.0

Palmitlc (substantially) c.5- a.o

The term rosinic-fatty type acid, as used in connection with the present invention, contemplates the inclusion of (a) a physical mixture of one or more rosinic acids with one or more soapforming fatty type acids; (b) chemically combined rosinic acid and fatty type acid, such as the rosin-malelc acid condensation productlater described which is a single compound which is both rosinic acid and fatty type acid as defined in this specification; (c) mixtures of (b) with a soap-forming fatty type acid; (it) mixtures of (b) with a rosinic acid; with (a) The present invention may best be understood by considering the following specific examples, in which all parts are given by weight:

EXAMPLE 1 This example is taken from my cofiled application, Serial No. 479,495, referred to above.

Gxarmc' Ran Plenum-The calcium salt of the coupling of Z-nuphthulamine-I -sullonic acid with See Schultz, "Farbstofltabellen" (1931), No. 219.-Prepare 485 parts of water containing well slurried pigment pulp, still wet from the forming process and in the amount of 17.5

and (e) mixtures-of (b) from Also cations other than the alkali parts (dry content). If desired, 0.39 part of the condensation product of naphthalene sulfonic acid and formaldehyde, dissolved in parts of water, may be added to assist in the dispersion of the pigment in water. Then add.0.39 part of perilla oil fatty acids, as the sodium salts in a ,10% aqueous solution. To this add 0.37 part of barium chloride (BaClz.2H2O) dissolved in 10 parts of water. Then add 0.78 part of a condensation product of approximately 1 part of maleic anhydride and 6.8 parts of E. wood rosin,

as the-sodium salt in a 10% aqueous solution. Then add 0.62 part of barium chloride (BaCl2.2HzO) in 10 parts of water. This point in the procedure is designated stage A, for reasons appearing below.

Up to this point, it is seen that one insoluble soap is built upon another. A special excess of 2.0 parts of barium chloride (BaClz.2Hz0) in 20 parts of water is then added, followed by minutes agitation. Then filter, and dry without washing. The dried pigment is designated product B.

During the above' process, the temperature of the slurry is preferably kept at 50 to 55 C. While the temperature is not critical, it does affect the rate of the precipitation reactions. It is desirable to maintain, for standardized products,'a rather close control of temperature, be-

cause a deviation from a prescribed temperature in some cases affects the value of the color. The preferred temperature in this example has been found to give the particular results which applicant desires, and need be followed closely only trolyte which may have come into the original pigment slurry as a result of any incomplete washing of the pigment after its formation. The

total acid content of the soaps is 6.7% of the origparts of barium chloride (BaCI22H2O). 'Heat at v inal pigment, being 2 parts of rosinic acid to 1 a part fatty type acid. The salt electrolyte retained is variable withthe character of the procedure, especially the filtration.

The following comparison shows particularly the advantages of salt electrolyte'in the pigment.

At stage A, above referred to, the pigment is ill-.-

tered, thoroughly washed, and dried, giving prod uct A. Then product B, resulting fromthis example as completed, is compared with product A'.

Two inks were prepared having 20 parts of p'gment to 24 parts of No. 0 regular litho varnish (a bodied linseed oil), called, respectively, ink A and ink B, from the pigments used therein.

In]: body.-lnk' B shows a radical improvement over ink A prepared from the pigment containing no salt electrolyte, in terms of body-softnesandflow. r

Lithogr phic breakdown resistance-A very marked improvement is shown by ink B over ink.

Aprepared from the pigment containing no salt electrolyte.

Exsurns2 This example is taken from my cofiled application, Serial No. 479,496, referred to above.

rides a pigment having present a water-insoluble pithy of Z-naphthylamine-I-sulfonic acid with z-naphthol. (See Schultz, Farbstofitcbellen" (1931), No, 219) .-Into 300 parts of water, place 8.5 parts of sodium hydroxide and 43.9 parts of Z-naphthylamine-l-sulfonic acid (98.5% Purity) With gentle warming, stir to solution. Cool to 0 C. by means or ice addition. Then add 57 parts parts of Z-naphthol to form the alkaline color-.

component solution. With the latter at 20 (3.,

add to it the prepared diazo, thus striking the.

dyestuii, which is now present as the acid-form in the presence of sodium ion in a medium at about 13 C. This is referred to as the strike."

To the strike at 13 0., add the following three aqueous soap solutions:

(a) 7.2 partsof WW wood rosin, as the sodium salt in a. 10% solution;

(b) 7.2 parts of a maleicacid-rosln condensation product "(prepared by condensing approximately 1 part of maleic anhydride with 6.8

parts of E wood rosin), as a sodium salt in a 10% solution; and

(c)"7.2 parts of crude naphthenic acids, as the sodium salts in a 10% solution;

and then dilute with cold water to a 100% volume increase. l Separately prepare a solution at 70 to 80 C. of 1800 parts of water and 17.8 parts of barium chloride (BaCl2.2H2O). Add-the soap-containing strike slowly, as required, to the heated salt solution, while stirring and maintaining the temperature at 70 to i C. Upon completion of the slurry addition, flood with cold water to C. Then add a solution of 120 parts of water and 12 the boiling temperature'fo'r 10 minutes, and flood with cold water to a temperature of C. Add 12 parts of barium chloride (BaCh.2Hz0) dissolved in 120 parts-water. Stir for a short time, ifilter, do not wash, and dry. 20 parts of such pigment are readily ground into 24 parts of No. 0

regular. litho varnish to make an improved ink.

Discussion.The last addition of barium chloride is for the purpose of introducing salt electro-f lyte. The failure to wash is or the purpose of retaining a portion of this and other salt electrol'yte, largely sodium chloride, present in the suspending liquid which ,is largely filtered away.

=It is to be observed thatthe above example prometallic soap of a rosinic acid and a water-insoluble metallic soap of a fatty type acid. A pig ment having this combination of soaps, rather than but one of such soaps, is of itself improved for the purpose of making inks, and it isof itself subject to further improvement by the presence of the salt electrolyte. The effectiveness of salt electrolyte to give improved inks, is greatly enhanced by the presenceof a combination of soaps,

one of which isderived' from a rosinic soap-form.-

ing acid, and the other of which is derived from 7 .a fatty type soap-forming acid. Salt electrolyte in'the pigment results in better wetting when incorporating the pigment and soap into a vehicle.

It also produces coating compositions having increased flow and, in the case 01' certain inks. gives GRAPHIC Rsn Promim' Bar-ium suite! the couimproved lithographic breakdown resistance.

' that the composition is desired.

1 Exunns 3 I This example is in part taken from my coflled application Serial No. 479,494, referred to above.- Graeme Ra PIGMENTTh8 barium salt of the coupling of Z-naphthylamine-l -sulfonic acid with Z-naphthol. See Schultz, Farbstofltabellen (1931), No. 219.-To an agitated solution at 90 C. produced from 450 parts of water; 6.0 parts of WW wood rosin, as the. sodium salt in a 10% solution in water; 6.0 parts of the condensation product of about 1 part of maleic anhydride and 6.8 parts of E wood rosin, as the sodium salt in a 10% solution in water; and 6.0 parts of crude naphthenic acids, as the sodium salts in a 10% solution in water, add 10.5 parts of barium chloride (BaCl2.2H:O) dissolved in 200 parts of water.

and maintained the temperature at 90 C., filter 03 the resulting water-insoluble metallic soap. Wash free of salt electrolyte, dry,'and grind to a powder. For convenience. this' soap is designated "soap A.

The preparation of soap A is repeated, save 10.5 parts of barium chloride (BaClz.2HzO) are increased to 14.0 parts to provide additional salt electrolyte, and no washing is practiced after the filtration. For convenience, this soap is designated as "soap B."

Soap B, in appearance, closely resembles that of soap A. It differs, however, in that adhering or occluded salt electrolyte is present, both as a result of eliminating the washing stepand also due to an increase in the amount of the barium chloride.

. By conventional methods acoating composition is prepared from the following ingredients:

Parts by weight Barium graphic pigment 17 Soap A 3 No.0 regular litho varnish 24 This ink is for convenience designated ink C."

Another coating composition is similarly prepared, except that soap A is replaced by soap B.

This ink is for convenience designated ink D.

with the soap powder, it may be associated with the pigment, preferably during the pigment fornaphthol. (See Schultz, "Farbstofitabellefl (1931), No. 219).Into 300 parts of water, place 8.5 parts of sodium hydroxide, and 43.9 parts of 2-naphthylamine-1-sulfonic acid (98.5% purity). With gentle warming, stir to solution. Cool to 0 C. by means of an ice addition. Then add 57 parts of 28% by weight hydrochloric acid. Di-

' azotize at 0 'to 2 C. with 13.8 parts of sodium After 15 minutes agitation, while having attained at about 13 C. This is referred to as the strike. I

To the strike at 13 0., add 21.6 parts of WW wood rosin, as the sodium salt in a 10% aqueous solution. Then dilute with cold water to a 100% volume increase.

Separately prepare a solution at 70 to 80 C- of 1800 parts of water and 17.8 parts of barium chloride '(Bach.2mo). Add the soap-containing strike slowly, as required, to the heated salt Q 'solution, while stirring and maintaining the temperature at 70 to 80 0. Upon completion of the slurry addition, flood with cold water to 0. Then add a solution of 120 parts of water and 12 parts of barium chloride (BaCh.2I-Ia0). Heat at the boiling temperature for 10 minutes, and flood with cold water to a temperature of 0. Add 12 parts of barium chloride (Bath-2.21120) dissolved in 120 parts of water.

Stir for a short time, filter, thoroughly wash, and

then dry. The pigment product at this stage is for convenience designated "pigment C. 20 parts of such pigment are readily ground into 24 parts of No.0 regular litho varnishto make an mation or conditioning process; or, if desired, at

any time prior to, or even after, the final drying of the pigment. For example, the salt electrolyte necessarily present after formation of the original strike of an azo pigment dyestufi, may be reing and final recovery steps by omitting the customary washing step prior to drying. This salt .lyte, either before or after drying. Alternatively, part of the salt electrolyte may be associated with the dry-pigment and part with the soap powder at the most convenient stagesprior to mixing the latter with the former, where a new dry pigment I Exmtn 4 Gmirnrc Ran Fromm-Barium salt of the coupling of Z-naphthylamine-I-sulfohic acid with"?- tainedwith the pigment through the conditionink.

\ If the slurry from above is processed without any washing prior to drying, as was performed in producing pigment C, and then dried and ground, a pigment is obtained containing some salt electrolyte. For convenience this pigment is designated pigment D. 20 parts of this pigment are readily ground into 24 parts of No. 0 regular litho varnish to make an ink.

The ink secured from pigment D, when compared with an ink secured from pigment C, shows somewhat better softness and length of ink body.

This example illustrates the use of salt electrolyte with an azo pigment dyestuff lake containing a single water-insolul-e metallic soap. The improvements here are not as great as in Examples 1 to 3. However, they are advan ous and demonstrate that the advantage of us;-.g salt electrolyte is not confined to pigments associated with a mixture of the soaps of the types disclosed in my copending applications discussed above, and inhere in the combination of salt electrolyte and any water-insoluble metallic soap, when both are present with any azo pigment dyestufi.

affect to some 'extent'the physical form ofthe completed pigment dyestuff.

It has been found that, under certain conditions, the presence of salt electrolyte with an azo pigment dyestuif containing no soap extender of any kind tends to give slightly improved wetting of a pigment by a vehicle, as well as slightly beneficial flow properties of the finished coating composition. The improvements here, however, are of a very small order compared to the improvements resulting from the additional presence of water-insoluble metallic soap.

In the foregoing examples, the saltingredient used to provide additional salt electrolyte was barium chloride. However, it is to be understood that the nature of the salt used for this purpose may vary widely within the definition of salt electrolyte given herein and that, even in the above examples, other salts than barium chloride are necessarily present in the final product. In Example I, for instance, the soluble salts present in the suspending liquid after precipitation of the insoluble soaps consist of salt formed during the coupling reaction in forming the initial pigment compound, salt 'formed in converting the be provided merely by adding an excess of the water-soluble salt used to precipitate either the pigment, or the soaps, or both;

Obviously, not all of the salt electrolyte present in the aqueous slurry of the soaped pigments of Examples land 2, or present with the precipitated soap B of Example 3 prior to filtering, is retained with the pigment by not washing it.

' The amount retained may be diminished or increased asconditions may require by control of the separation from the liquid. or by a controlled partialwashing, or increased by the addition of salt electrolyte at any time up to incorporation of the pigment into the vehicle. In the dry process, the salt electrolyte may be added to the wet soap before drying. or it may be added in powdered form to the finished soap nroduct,-though such additions are not preferred.

With res e t to the dry nrocess of Example 3, it has been found that cation salts, other than the alkali-metal ty e, tend to react unfavorably under certain cond tions in the presence of certain alkali metal salt forms of azo pi ment dyestuffs. In general. advantageous and adaptable use of salt electrolyte having such cations in the soap powders. is made with 920 pi ment dyestuffs other than the alkali metal salt-forms.

I have given above a number of examples involving various manipulat ons with and without the ste of retaining sa t e ectrolyte with the pigment, or w th the soa with which the pigment is associated. The fundamental chemistry involved in forming the pi ments has not been changed where salt electrolyte has been retained, but variations of the final steps of the recovery procedure of either the pigment or the soap are assumes so made that the physical properties of the saltelectrolyte-soap-pigment compositions. when incorporated into a vehicle, are improved. In particular, the surface of the pigment particles is believed to be so modified that it presents new properties, whereby the interfacial relation of solid (pigment) to liquid (vehicle) has been changed to a more favorable one. Thus, the new pigment compositions present improved grinding and wetting properties toward numerous vehicles commonly employed in the industry. Besides afiecting the physical chemistry of the pigments in a manner such as has just been de scribed, salt electrolyte in the presence of waterinsoluble metallic soap has been shown to effect greater emulsion inhibition in azo pigment dyestuif inks, that are used for the wet lithographic process.

While I have briefly referred to a theory explaining in part the nature of the physical changes occurring in the behavior of the new azo pigment dyestufi compositions when incorporated into a'vehicle, I intend in no way to suggest that such explanation constitutes any limit upon the scope of my invention. Likewise, the examples which I have given to illustrate several different practical applications of the present invention are not intended to be construed as limitations. Numerous procedures for making azo pigment dyestuff coating compositions in which my invention may be readily applied will be apparent to one skilled in the art.

This application is a continuation in part of my copending applications, Serial Nos. 348,687 to 348,690 inclusive, all filed July 31, 1940; and Serial Nos'. 427.919 and 427,920, both filed January 23, 1942. This application is also generic to my cofiled applications, Serial Nos. 479,493, 479,494, 479,495, 479,496, 479,498, and 479,499.

What I claim as my invention and desire to secure by Letters Patent is:

l. The method of making a coating composition which comprises simultaneously dispersing azo pigment dyestuff, water-insoluble metallic soap, and a small amount of salt electrolyte into a non-aqueous liquid vehicle.

2. The method of making a coating composition which comprises simultaneously dispersing into a non-aqueous liquid vehicle dry materials comprising essentially azo pigment dyestufi, water-insoluble metallic soap, and a small amount of salt electrolyte.

3. In the manufacture of azo pigment dyestuif coating compositions, the improvement which comprises associating a small amount of salt electrolyte, water-insoluble metallic soap, and azo pigment dyestufi', and incorporating the resulting composition into a non-aqueous liquid vehicle.

ing a minor portion thereof sumcient to provide a small amount of said dissolved saltelectrolyte in the said pigment-soap composition.

6. The process of manufacturing an azo pigment dyestufi composition which comprises assoclating water-insoluble metallic soap with azo pigment dyestufi in 'a suspending liquid containing dissolved salt electrolyte, separating the resulting pigment-soap composition from the major part of the suspending liquid while retaining a minor portion of said liquid, and drying the said composition without washing, whereby a small amount of salt electrolyte is retained therewith.

7. The process of manufacturing an azo pigment dyestuil' composition which comprises forming water-insoluble metallic soap in dry powdered form, separately forming an azo pigment dyestuff in dry powdered form, physically associating a small amount of salt electrolyte with at least one of said materials during its formation and retaining it therewith, and mixing together the powdered pigment and the powdered soap.

8. The process of manufacturing an azo pigment dyestufi composition which comprises forming water-insoluble metallic soap in dry powdered form while physically associating and retaining a small amount of salt electrolyte therewith, separately forming an azo pigment dyestufl in dry powdered form, and mixing the powdered pigment with the powdered soap and associated salt electrolyte.

9. The process of manufacturing an azo pigment dyestufi composition which comprises forming water-insoluble metallic soap in dry powdered form, separately forming an azo pigment dyestuff in dry powdered form while physically associating and retaining a small amount of salt electrolyte therewith, and mixing the powdered soap with the powdered pigment and associated salt electrolyte.

10. The process of manufacturing azo pigment dyestutl coating compositions which comprises associating azo pigment dyestuff and water-insoluble metallic soap in a suspending liquid containing dissolved salt electrolyte, separating the azo pigment dyestufi and water-insoluble soap from the suspending liquid in such manner as to retain a small amount of the salt electrolyte with the pigment and soap, and incorporating the pigment. soap, and the retained salt electrolyte into a non-aqueous liquid vehicle.

11. In the process of manufacturing azo pigment dyestufi coating compositions containing a dry powdered mixture of azo pigment dyestufl,

water-insoluble metallic soap, amount of salt electrolyte.

13. The process of manufacturing azo pigment dyestufi coating compositions which comprises incorporating into a non-aqueous liquid vehicle a dry powdered mixture of azo pigment dyestufi, water-insoluble metallic 'soap, and a small amount of salt electrolyte, said salt electrolyte havingbeen intimately associated with at least oneof the other two constituents of the powdered mixture during its preparation and prior to mixing the said two constituents.

14. The process of manufacturing azo pigment dyestuff coating compositions which comprises forming water-insoluble metallic soap in dry powdered form, separately forming an azo pigment dyestuif in dry powdered form, physically associating a small amount of salt electrolyte with at least one of said powdered materials during its formation and retaining it therewith, mixing together the powdered pigment and the powdered soap whereby salt electrolyte is included in the resulting mixture, and incorporating said mixture into a non-aqueous liquid vehicle.

15. A pigment composition comprising in intimate association azo pigment dyestuff, water-insoluble metallic soap, and a small amount of salt electrolyte.

16. A pigment composition comprising azo pig ment dyestuif, water-insoluble metallic soap, and a small amount of salt electrolyte, all intimately associated together by the process of claim 5.

17. A dry pigment composition comprising azo pigment dyestufi, water-insoluble metallic soap, and a small amount of salt electrolyte, all intimately associated together by the process of claim 6.

18. An azo pigment dyestuif composition comprising azo pigment dyestufi, water-insoluble metallic soap, and a small amount of salt electrolyte, all associated together in dry powdered form by the process of claim "I.

19. A coating composition comprising a nonaqueous liquid vehicle, and dispersed therein: azo pigment dyestuff, water-insoluble metallic soap, and a small amount of salt electrolyte, associated togetherprior to dispersion in said vehicle.

20. A coating composition comprising a nonaqueous liquid vehicle having incorporated therein an azo pigment dyestuif composition prepared by the process of claim 5, and comprising azo pigment dyestuff, water-insoluble metallic soap, and a small amount of salt electrolyte.

21. A coating composition comprising a nonaqueous liquid vehicle having incorporated therein an azo pigment dyestufi composition prepared by the process of claim 6, and comprising azo pigment dyestufi, water-insoluble metallic soap, and a small amount of salt electrolyte.

22. A coating composition comprising a nonaqueous liquid vehicle having incorporated therein an azo pigment dyestuff composition prepared by the process of claim '7, and comprising azo pigment dyestufl, water-insoluble metallic soap, and a small amount of salt electrolyte.

GRADY M. O'NEAL.

and a small Patent- No. 2,350,52LL.

CERTIFICATE OF CORRECTION;

- June 6, 191 1;.

GRADY n. O'NEAL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, sec- 0nd column, line' 52, for "present" read --apparent-; page'Z, second column, line 15, for "said" read ealt--; arid that the said Letters Patent hould be read with this correction therein that the same may conform to the record ofthe case in the Petent Office Signed and sealed this 29th day of August, A. D. 191411..

Leslie Frazer (Seal Q) Acting Commie sioner of Patents. 

